The present invention relates generally to a resin composition, particularly halide impregnated resin particles, and to a method of making the same. The halide impregnated resin particles may be applied to a substrate in the form of a coating or a dry aerosol. It is believed that the halide impregnated resin particles may be used to deactivate or substantially reduce the effectiveness of certain chemically and biologically active agents on contact. Thus, the present invention also relates to the use of halide impregnated particles to deactivate certain chemically and biologically active agents.
U.S. Pat. No. 5,639,452 to Messier, the content of which is incorporated herein by reference, discloses a disinfectant substance comprising an iodine impregnated ion exchange resin and a process for the preparation thereof. The Messier patent discloses that this disinfectant is a demand-type broad spectrum resin-polyiodide disinfectant useful in sterilizing fluids, and particularly a polyiodide disinfectant in which the iodine is more tenaciously associated with the resin than with previously known disinfectants, such that it leaves behind nondetectable or otherwise acceptable residual diatomic iodine in treated fluids. Thus, the patent teaches that the iodinated resin may be used to sterilize fluids such as water, air, and bodily secretions by devitalizing microorganisms such as fungi, bacteria and viruses that may be present in the fluid. It appears that this effect generally is accomplished by causing the microorganisms in the fluid to contact the resin surface and/or the resin impregnated material. U.S. Pat. No. 5,431,908 to Lund, the content of which is incorporated herein by reference, also teaches a method of preparing halide-impregnated ion exchange resins useful in purifying fluids such as water.
A devitalizing or disinfectant substance that incorporates the capabilities of a fluid disinfectant such as that described by Messier or Lund, but that is suitable for use in connection with the disinfection of nonfluid objects and deliverable in aerosolized form or incorporated into a coating would be desirable. Such a substance could be used, for example, to decontaminate a nonfluid object that is exposed to biological agents such as airborne pathogens, whether continuously or intermittently. It also could be used to provide a protective coating on nonfluid objects that are likely be exposed to biological agents such that the object would be capable of devitalizing these agents on demand, at least until the devitalizing substance present in the coating has been exhausted, without significant detriment to the object""s usual utility and without application of a discrete decontamination or devitalization substance or procedure after exposure to the agent. Such a protective coating would be useful on objects that are likely to be exposed to biological agents on a more or less regular basis, for example, equipment used in medical emergency response or other health care applications or surfaces in public or institutional washrooms and shower facilities. The coating also would be useful on objects that may be exposed to such agents in the event of a catastrophe, such as a military conflict, terrorist incident or a hazardous material spill.
As used herein, xe2x80x9cbiological agentxe2x80x9d refers to hazardous biological organisms including viruses and bacteria, whether in the form of spores or otherwise, and eukaryotic parasites such as Giardia. It also includes biologically generated toxins such as botulinum toxin. The term xe2x80x9cdevitalizexe2x80x9d means to kill a biological agent that is an organism, or to render a biological agent inactive or substantially less effective, including, without limitation, disinfection. It is expected that the devitalizing substance will be effective against biological agents that are susceptible to oxidation by ionic halides such as polyiodide ions.
It also would be desirable to have a deactivating substance capable of reaction with and at least partial deactivation of certain chemical agents. As used herein, xe2x80x9cchemical agentxe2x80x9d means a hazardous chemical agent, including but not limited to chemical warfare agents such as the compounds known as GD, HD and VX, and hazardous industrial chemical agents. Also, the term xe2x80x9cdeactivatexe2x80x9d means to render any such chemical agent inactive, ineffective, or substantially less effective for its intended purpose of causing harm to animal life or health, and particularly human life or health. As described above in connection with devitalization of biological agents, it is expected that the deactivating substance will be effective against chemical warfare agents and other chemical agents susceptible to oxidation by ionic halides such as polyiodide ions.
The above-described chemical agent deactivating substance could be used to decontaminate fluids that may contain chemical agents, to decontaminate nonfluid objects that may have such agents on their surfaces, or to provide a protective coating on nonfluid objects that are likely to be exposed to such agents. Such a protective coating may provide increased resistance to chemical agents even if it is not capable of deactivating all such possible agents. A substance capable of devitalizing biological agents and deactivating chemical agents, either independently or simultaneously depending upon the circumstances, would be particularly preferred.
In connection with the use of a devitalizing or deactivating substance to decontaminate nonfluid items, it further would be desirable to have such a substance in a dry aerosol form, such that finely divided particles of the substance may be dispersed over the item or items to be treated. Dispersal of the dry aerosol substance, for example, by fogging a room, would allow the substance to penetrate into pores, crevices or other surface irregularities that may be present in or on the item(s) to be treated. The substance also could be applied in this manner to contaminated items such as computers, electronic and electrical equipment, and other water-sensitive or water-reactive materials, that may be further harmed by contact with a liquid devitalizing or deactivating substance, and particularly a water-based substance. A suitable substance in dry aerosol form may be selected based on the electrostatic properties of a nonfluid item, such that the resin particles deposited on the surface tend to be held in engagement with the surface for a period of time. Alternatively, for nonfluid objects that are not liquid-sensitive, the dry aerosol substance may be applied to a surface that has been treated by wetting with a suitable wetting agent to cause the resin particles to remain in engagement with the surface for a desired length of time.
A dry aerosol also could be used in forming a protective coating on a substrate, for example, by xe2x80x9cdust-coating.xe2x80x9d The devitalizing or deactivating substance in dry aerosol form could be applied to a wetted surface. The wetting agent causes the resin particles to be adhered to or within the agent, such that the particles remain in contact with the surface after drying or curing of the wetting agent. For example, the wetting agent may be a paint-type coating such as a chemical warfare agent resistant coating (CARC) or a polymeric composition.
It also would be desirable to cause the devitalizing or deactivating substance to be incorporated into a coating that may be applied to nonfluid objects to form a protective coating thereon. The resin particles may be admixed with a suitable carrier and the resultant coating applied to a surface of the object by any suitable means, for example, brushing, rolling, spraying, troweling, pouring or the like. The carrier may be a paint-type coating such as a water- or solvent-based CARC or a polymeric material. Such a coating that could be applied to objects likely to become exposed to chemically or biologically active agents, such that deactivation and devitalization of these agents could begin on contact with the object and the object could be maintained essentially free from contamination by such agents during the effective life of the halide-resin composition.
In addition, it would be advantageous to have a halide-resin composition that has characteristics superior to known iodide-resin disinfectants. For example, a halide-resin having an increased surface area to provide more rapid deactivation of biologically active agents, and particularly a finely divided resin suitable for dispersion as a dry aerosol, would offer advantages. A halide-resin composition capable of deactivating, or at least partially deactivating, chemically active agents such as nerve gases in addition to biologically active agents, also would offer particular advantages.
These and other objects of the present invention will be apparent from the specification that follows and the appended claims.
In accordance with these objectives, a resin composition capable of devitalizing biological agents and deactivating chemical agents may comprise halide-resin particles comprising polyhalide ions having a valence of xe2x88x921 absorbed or impregnated into resin particles having a particle size substantially in the range of about 0.1-15 microns. The halide-resin may be characterized in that an activated halogenated resin is divided into particles substantially in the range of about 0.1-15 microns before exposure to a sufficient amount of a halogen-substance absorbable by the activated resin to form converted resin particles having a greater proportion of available ionic halogen, with the halogen-substance being selected from the group consisting of I2, Br2, and polyiodide ions having a valence of xe2x88x921. The halide-resin particles may, for example, have a particle size substantially in the range of about 0.1-3 microns, 3-5 microns, 3-15 microns, or 5-15 microns.
The resin composition also may comprise halide-resin particles comprising polyhalide ions having a valence of xe2x88x921 absorbed or impregnated into resin particles and characterized in that an activated halogenated resin is divided into particles substantially in the range of about 15-300 microns before exposure to a sufficient amount of a halogen-substance absorbable by the activated resin to form converted resin particles having a greater proportion of available ionic halogen. The halogen-substance is selected from the group consisting of I2, Br2, and polyiodide ions having a valence of xe2x88x921.
As used herein, the terms xe2x80x9cpolyhalide,xe2x80x9d xe2x80x9cpolyhalide ions,xe2x80x9d and the like refer to or characterize a substance or a complex that has three or more halogen atoms and a valence of xe2x88x921, and which may be formed if a molecular halogen (e.g., bromine as Br2) combines with a monovalent trihalide ion (e.g., triiodide ion) or pentahalide ion (e.g., pentaiodide ion). Iodine and chlorine also may be used as a source of molecular halogen. Similarly, the terms xe2x80x9cpolyiodide,xe2x80x9d xe2x80x9cpolyiodide ions,xe2x80x9d and the like refer to or characterize a substance or a complex that has three or more iodine atoms and that may be formed if molecular iodine combines with the monovalent triiodide ion. The terms xe2x80x9ctriiodide, xe2x80x9ctriiodide ion,xe2x80x9d and the like refer to or characterize a substance or a complex that contains three iodine atoms and has a valence of xe2x88x921. The triiodide ion herein therefore is a complex ion which may be considered as comprising molecular iodine (i.e., iodine as I2) and an iodine ion (i.e., Ixe2x88x92).
The above-described converted resin particles may be capable of being dispersed in dry aerosol form. The converted resin may be capable of reducing the activities of target chemical agents, biological agents, and biologically generated toxins. A single resin may be capable of reducing the activities of both chemical and biological agents. The devitalizing and deactivating resin may be a demand-type devitalizer and deactivator, i.e., a substance from which halide ions are released almost entirely on a demand-action basis upon contact with a target agent but that does not otherwise release substantial amounts of the devitalizing and deactivating substance into the environment. Such a demand-type substance essentially would be capable of devitalizing and deactivating target agents on demand, at least until the halide-resin has been exhausted.
The invention includes a method of making a resin composition, comprising the steps of:
providing an activated halide-resin;
forming the activated resin into particles;
selecting resin particles substantially in the range of about 0.1-300 microns; and
forming converted resin particles having a greater proportion of available ionic halogen.
The step of selecting resin particles may, for example, include selecting particles substantially in the range of about 0.1-3 microns, 3-5 microns, 3-15 microns, 5-15 microns, or 15-300 microns. It also may include selecting an anionic triiodide resin or a divinyl styrene triiodide resin.
Converted resin particles may be formed by exposing the resin particles to a sufficient amount of a halogen-substance to form converted resin particles, the halogen-substance being selected from the group consisting of I2, Br2, and polyhalide ions having a valence of xe2x88x921. Absorption of at least a portion of the halogen-substance may be effected at elevated temperatures, i.e., temperatures higher than 100xc2x0 C. and up to 210xc2x0 C., and elevated pressures, i.e., pressures greater than atmospheric pressure and up to 100 psig.
The present invention also provides a demand chemical-agent deactivator, comprising halide-resin particles comprising polyhalide ions having a valence of xe2x88x921 absorbed or impregnated into resin particles having a particle size substantially in the range of about 0.1-300 microns. The resin particles of the deactivator may, for example, have a particle size substantially in the range of about 0.1-3 microns, 3-5 microns, 3-15 microns, 5-15 microns, or 15-300 microns. The resin may be an anionic resin, a divinyl styrene resin, or a quaternary ammonium resin. The halide-resin particles may be polyiodide-resin particles, which may be predominantly triiodide-resin particles. The deactivator may be capable of being dispersed in dry aerosol form.
The invention also provides a method of deactivating target agents, comprising the steps of:
providing an activated halide-resin;
forming the activated resin into particles;
selecting resin particles substantially in the range of about 0.1-300 microns;
exposing the resin particles to a sufficient amount of a halogen-substance absorbable by the activated resin to form converted resin particles having a greater proportion of available ionic halogen, the halogen-substance being selected from the group consisting of I2, Br2, and polyhalide ions having a valence of xe2x88x921; and
placing the converted resin particles in contact with a target agent selected from chemical agents, biological agents, and biologically generated toxins. Absorption of at least a portion of the halogen-substance may be effected at elevated temperatures and elevated pressures as described above.
The step of selecting resin particles may include selecting particles substantially in the range of about 0.1-3 microns, 2-3 microns. 3-5 microns, 3-15 microns, 5-15 microns, 15-50 microns, or 15-300 microns. The step of providing an activated halide-resin may include selecting an activated halide-resin having a electrostatic charge that assists in maintaining converted resin particles in engagement with a substrate.
In accordance with the objective of using the converted resin for decontamination of nonfluid objects, the step of placing converted resin particles in contact with a target agent may include dispersing the converted resin particles as a dry aerosol, imparting an electrostatic charge to the converted resin particles to assist in maintaining them in engagement with a surface, or providing a surface that is electrostatically charged to maintain the converted particles in engagement with the surface. The step of placing converted resin particles in contact with a target agent also may include providing a wetted surface and causing a portion of the converted particles to be deposited on the wetted surface. The step of providing a wetted surface may include selecting a surface wetting agent capable of retaining converted resin particles deposited on a surface wetted with the wetting agent.
In accordance with the objective of using the converted resin in a protective coating, the step of placing converted resin particles in contact with target agent may include the steps of:
providing a carrier capable of holding the converted resin particles in suspension;
suspending the converted particles in the carrier; and
applying the suspension to a surface.
The step of providing a carrier may include selecting a carrier that does not materially interfere with the ion exchange capability of the converted resin or that comprises a chemical agent resistant coating. This step also may include providing a predetermined volume of pigment particles and the step of suspending the converted resin particles in the carrier may include suspending a volume of converted resin particles approximately equal to the volume of pigment particles.
The invention also includes an aerosol capable of reducing the effectiveness of target agents, such as chemical agents, biological agents, and/or biologically generated toxins. The aerosol substance comprises halide-resin particles comprising polyhalide ions having a valence of xe2x88x921 absorbed or impregnated into resin particles and characterized in that an activated halogenated resin is divided into particles substantially in the range of about 0.1-300 microns before exposure to a sufficient amount of a halogen-substance absorbable by the activated resin to form converted resin particles having a greater proportion of available ionic halogen, with the halogen-substance selected from the group consisting of I2, Br2, and polyiodide ions having a valence of xe2x88x921. The halide-resin particles may be further characterized in that an activated halogenated resin is divided into particles substantially in the range of about 0.1-3 microns, 3-15 microns, or 15-300 microns before exposure to the halogen-substance.
The converted resin particles are capable of being dispersed as a dry aerosol. The particles may be electrostatically charged to assist in maintaining the particles in engagement with a substrate, with the particles being electrostatically charged prior to being dispersed. Preferably, the electrostatic charge difference between the particles and the substrate will be sufficient to permit the particles to adhere to vertical surfaces and the like. The converted resin particles may, for example, be passed through a nozzle so that they engage a static charge inducing substance in the nozzle.
The invention also includes a coating capable of reducing the effectiveness of target agents. The coating comprises halide-resin particles comprising polyhalide ions having a valence of xe2x88x921 absorbed or impregnated into resin particles and characterized in that an activated halogenated resin is divided into particles substantially in the range of about 0.1-300 microns before exposure to a sufficient amount of a halogen-substance absorbable by the activated resin to form converted resin particles having a greater proportion of available ionic halogen, with the halogen-substance being selected from the group consisting of I2, Br2, and polyiodide ions having a valence of xe2x88x921; and a carrier holding the converted resin particles in suspension. The converted resin is capable of reducing the effectiveness of targets including chemical agents, biological agents, and/or biologically generated toxins.
The halide-resin particles may be further characterized in that an activated halogenated resin is divided into particles substantially in the range of about 0.1-3 microns, 3-15 microns, or 15-300 microns before exposure to the halogen-substance. The converted resin particles are at least 20 percent larger than the particles of any pigment present in the carrier.
The carrier preferably does not materially interfere with the ion exchange capability of the converted resin. The carrier may be a chemical warfare agent resistant coating, a hazardous industrial chemical resistant coating, a coating that is selectively permeable to specific fluids, or a latex. The carrier may include a predetermined volume of pigment particles and the volume of converted resin particles suspended in the carrier may be approximately equal to the volume of pigment particles. The combined volumes of the pigment particles and the converted resin particles may approach the critical pigment volume of the carrier or be at least about 90% of the critical pigment volume of the carrier.
The invention further includes a method of making a protective coating, comprising the steps of:
providing an activated halide-resin;
forming the activated resin into particles;
selecting resin particles substantially in the range of about 0.1-300 microns;
exposing the resin particles to a sufficient amount of a halogen-substance absorbable by the activated resin to form converted resin particles having a greater proportion of available ionic halogen, the halogen-substance being selected from the group consisting of I2, Br2, and polyhalide ions having a valence of xe2x88x921;
providing a carrier capable of holding converted resin particles in suspension; and
suspending the activated particles in the carrier.
Absorption of at least a portion of the halogen-substance may be effected at elevated temperatures and elevated pressures.
The step of selecting resin particles may include selecting particles substantially in the range of about 0.1-3 microns, 3-15 microns, or 15-300 microns. This step also may include selecting particles that are at least twenty percent larger than the particles of any pigment present in the carrier.
The step of providing a carrier may include selecting a carrier that comprises a chemical agent resistant coating. The step of providing a carrier may include providing a predetermined volume of pigment particles and the step of suspending the converted resin particles in the carrier may include suspending a volume of converted resin particles approximately equal to the predetermined volume of pigment particles.
The method includes the step of selecting the predetermined volume of the pigment particles and a volume of converted resin particles such that the combined volumes approach the critical pigment volume of the carrier, or are at least about 90% of the critical pigment volume of the carrier. The method also may include the step of selecting a volume of the pigment particles and a volume of converted resin particles such that the combined volumes do not exceed the capacity of the binding resin in the coating to maintain the physical integrity of the cured coating with the extended pigment volume or the step of selecting a pigment particle density greater than the density of the resin particles.
The method may further include the step of selecting environmental conditions for drying the coating, the environmental conditions comprising a combination of cure temperature and relative humidity that yield a drying time sufficient to allow the resin particles to preferentially migrate to the coating surface. Preferably, the cure temperature is in the range of about 60xc2x0 to 90xc2x0 F. and the relative humidity is in the range of about 70 to 90 percent.
The step of providing a carrier may include selecting a carrier that does not materially interfere with the ion exchange capability of the converted resin. If the carrier interferes with the activity of the resin particles, the method may further include the steps of applying the coating to a substrate and treating the coating to improve the effectiveness of the resin particles. The treating step may include mechanically abrading or partially dissolving the coating surface to expose the resin particles such that their activity against target agents is unimpeded. The treating step also may include applying a fixative layer to the coating surface and adhering a layer of resin particles to the fixative layer.
These and further objects of the invention will become apparent from the following detailed description.